Door structure for a self-cleaning oven

ABSTRACT

Door structure for self-cleaning cooking apparatus of the pyrolytic type wherein substantially all of the heat for such purposes is supplied by a single heating element disposed near the top wall of the oven cavity. The door structure is characterized by the provision of an air duct which directs air therethrough such as to preheat the air prior to entry thereof into the oven cavity at the bottom thereof and passage across the front edge of the oven liner.

United States Patent inventors Calvin J. Holtkamp Mansfield; James A. Leach, Shelby, Ohio Applv No. 789,538 Filed Jan. 7, 1969 Patented Feb. 9, 1971 Assignee Westinghouse Electric Corporation Pittsburgh, Pa. a corporation of Pennsylvania DOOR STRUCTURE FOR A SELF-CLEANING References Cited Primary Examiner-Carroll B. Dority, Jr. Att0rneysF. l-l. Henson, E. C. Arenz and B. B. Sklar, Jr.

ABSTRACT: Door structure for self-cleaning cooking ap- 3 D paratus of the pyrolytic type wherein substantially all of the 'awmg heat for such purposes is supplied by a single heating element US. Cl 126/198, disposed near the top wall of the oven cavity. The door struc- 110/ 175 ture is characterized by the provision of an air duct which 1nt.Cl F23m 7/00 directs air therethrough such as to preheat the air prior to Field of Search 126/198, entry thereof into the oven cavity at the bottom thereof and 193; l 10/ l 75 passage across the front edge of the oven liner.

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INVENTORS Calvin J. Holikomp and James Av Leoc WITNESSES I 2 AGENT 1 DOOR STRUCTURE FOR A SELF-CLEANING OVEN BACKGROUND OF THE INVENTION This invention relates, in general, to self-cleaning cooking apparatus, and, more particularly, to door structures therefor.

In order to be totally acceptable to the consumer, the pyrolytic cleaning process in a cooking apparatus should clean all parts of the oven. That this is not accomplished, in some prior art constructions, is evidenced by the soiled conditions of the front lower lip or edge of the oven liner, after the cleaning cycle has terminated. The reason for this condition is the relatively low temperature of the air which, heretofore, by design, has been forced to enter the oven cavity in the area between the oven door structure and the front wall of the range, adjacent the bottom edge of the door structure. It has been determined that the relatively low temperature at the lip is on the order of 250 F. below the temperature at the center of the oven at cleaning temperatures.

Accordingly, the general object of this invention is to provide a new and improved cooking apparatus of the self-cleans yp It is a more particular object of the invention to provide, in a self-cleaning type of oven, a system for preheating the makeup air which is introduced into the oven cavity adjacent the lower edge of the liner delineating the cavity.

BRIEF SUMMARY OF TI-IEINVENTION Briefly, the above-cited objects are accomplished by the provision of adoor structure for a self-cleaning oven of the type wherein substantially all the heat for the cleaning cycle is furnished by a single heating element which element is adjacent the top wall of the oven liner. The door structure comprises an inner panel and an outer panel, the formerof which has a muffled insert structure attached centrally thereof. The muffled insert structure together with the inner and outer door panels define an air duct having two branches which direct makeup air upwardly through the door structure and then downwardly and into the oven liner. As the air flows along the duct, it picks up heat from the panels and the mufile insert structure.

While the provision of the duct constitutes additional cost to the overall door structure, it will be appreciated that the cost difference isnominal since, by thisconstruction it is possible to eliminate a substantial quantity of otherwise required insulation.

Further objects and advantages of the present invention will become more apparent when considered in view of the drawings and detailed description of the preferred embodiment, forming a part hereof.

DESCRIPTION OF DRAWINGS FIG. I is a right side elevational view of an electric range, partly broken away and partly in cross section, incorporating the invention;

FIG. 2 is a rear elevational view of the door structure incorporated in the range of FIG. 1; and

FIG. 3 is a cross-sectional view taken along the line 3-3 of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, especially FIG. 1, reference character designates generally a range comprising cabinet structure 11 having supported therein an oven structure 12. The oven structure comprises an outer shell 13 and an inner liner 14, the latter of which delineates an oven cavity 16.

The oven structure 12 has an opening 17 providing access to the cavity 16 through a door structure 18. For purposes of disclosure only, the range 10 is an electric unit, but it will be appreciated that the present invention is compatible with other units, for example, gas heated cooking apparatus. As is conventional in the art, there is provided a lower bake heating element l9 which is electrically accommodated by one of a plurality of receptacles 21. An upper broil heating element 22 is also provided, which together with, or apart from the heating element 19, may be employed in a conventional manner for normal cooking operations. As shown in FIG. I, the middle receptacle 2] may be used to receive an additional broiling element (not shown) for cooperating with the element 22 to simultaneously broil both surfaces of, for example, a steak.

In addition to its conventional broiling function, the element 22 is adapted by virtue of its location (i.c. adjacent the top wall 23 of the inner liner l4) and its operation as outlined in U.S. Pat No. 3,504,16l filed in the name of John C. Kastovich and assigned to the Westinghouse Electric Corporation, to pyrolytically clean the interior of the inner liner 14.

Since the cleaning mentioned above takes place at relatively high temperatures during operation of a heating element such as the element 22, thermal insulation 24 of suitable thickness is required. The insulation, which may be fiberglass or the like is installed between the inner liner l4 and the outer shell I3. Door structures found in the prior art, in like manner, are provided with insulation of like properties and thicknesses, however, the door structure 18 due to its construction, as will be apparent hereinafter, does not require the same quantities of insulation.

The structure 18 comprises a front panel 26 and a rear panel 27, the latter of which has a central opening 28 over which a muffle structure 29 is installed. While some insulation is installed between the panels 26 and 27 and between the panel 26 and the muffle 29, the quantity is substantially less than heretofore required. This is due to the provision of an air duct 31 in the door structure 18. The duct 31 comprises two branches 32 and 33, the former of which is delineated by insulation 24 and a wall segment 34 of the muffle structure 29, The air duct branch 33 is delineated by the wall segment 34 and the wall segment 36 of the muffle structure 29. The branches 32 and 33, as shown in FIGS. 1 and 3, are substantially coextensive with the height and width of the wall segment 36.

A transverse air inlet opening 37 adjacent the bottom of the door structure and an outlet 38 adjacent the bottom of the wall segment 36 are substantially coextensive with the width of the wall segment 36. Entry of air into the inner liner 14, from between thedoor structure 18 and the outer shell 13 is prevented by an annular gasket 40.

It will now be appreciated that there has been disclosed a self-cleaning cooking device 10 wherein the makeup air for supporting combustion within the cavity 16 is introduced thereinto, through an elongated opening 38. The air flows upwardly through the air duct branch 32 and downwardly through the air duct branch 33 thereby picking up heat from the muffle structure 29 and the surrounding areas. By providing such an arrangement, the temperature of the makeup air introduced into the cavity 16 adjacent the front edge 41 of the liner 14 provides improved cleaning over that which is possible with prior art systems of the type herein contemplated.

The rear panel 27 is secured to the front panel 26 by a pluralityof screws 39, the muffle structure 29, in turn, being secured to the rear panel 27 by a plurality of screws 40.

Since numerous changes may be made in the above described apparatus and different embodiments of the invention may be made without departing from the spirit thereof, it is intended that all matter contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

We claim:

1. Cooking apparatus of the type having a heat cleaning mode of operation and a cooking mode of operation and having walls delineating an oven cavity, said apparatus comprising:

means for supplying heat into said cavity from the upper space in said cavity during a heat cleaning operation; door structure comprising an outer panel, an inner panel structure and a muffle panel structure;

and defined between said inner and muffle panels branch. and extending for the major portion of the width and height of the door;

an elongated outlet opening for said second air duct branch in said door structure communicating with the interior of said oven cavity adjacent the lower front edge of said cavity said door structure being devoid of thermal insulation separating said air duct branches from said oven cavity. 

1. Cooking apparatus of the type having a heat cleaning mode of operation and a cooking mode of operation and having walls delineating an oven cavity, said apparatus comprising: means for supplying heat into said cavity from the upper space in said cavity during a heat cleaning operation; door structure comprising an outer panel, an inner panel structure and a muffle panel structure; a substantially vertically extending air duct branch between said inner and outer panels and extending for the major portion of the width and height of the door; a transverse elongated air inlet opening along the bottom edge of said door structure; means for mounting said door structure in registry with said oven cavity; a sealing gasket for preventing flow of air between said door and the front wall of said apparatus; a second substantially vertically extending air duct branch communicating with said first air duct at its upper end and defined between said inner and muffle panels branch, and extending for the major portion of the width and height of the door; an elongated outlet opening for said second air duct branch in said door structure communicating with the interior of said oven cavity adjacent the lower front edge of said cavity said door structure being devoid of thermal insulation separating said air duct branches from said oven cavity. 